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Head midline (central) position for preventing intraventricular hemorrhage (i.e., bleeding in the brain) in very preterm infants

Review question: Does head midline position reduce the risk of intraventricular hemorrhage (i.e., bleeding in the brain) and mortality in very preterm infants?

Background: Intraventricular hemorrhage (i.e., bleeding in the brain) occurs in 25% of very low birth weight infants and may be caused by multiple factors. Head position may affect how the blood circulates within the brain and thus may be involved in development of intraventricular hemorrhage. Turning the head toward one side may limit return of blood in the veins of the same side and may increase pressure and the amount of blood within the brain. It has been suggested that this might be avoided if the patient is in supine (lying on the back) midline (central) position, especially during the first two to three days of life, when risk of intraventricular hemorrhage is greatest.

Study characteristics: We included two studies comparing supine midline head position versus supine head rotated 90°.

Key results: This review of trials found too little evidence to show positive or negative effects of supine (lying on the back) midline head position for prevention of intraventricular hemorrhage (i.e., bleeding within the brain), mortality, or any other relevant outcomes in very preterm neonates. More research is needed. We found no trials that compared supine (lying on the back) versus prone (lying on the stomach) midline head position, and no trials that compared effects of head tilting (elevating the head of the incubator upward).

Conclusions: Results of this systematic review are consistent with beneficial or detrimental effects of a supine head midline position and do not provide a definitive answer to the review question.

Authors' conclusions:

Given the imprecision of the estimate, results of this systematic review are consistent with beneficial or detrimental effects of a supine head midline position versus a lateral position and do not provide a definitive answer to the review question.

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Background:

Preterm birth is known to constitute the major risk factor for development of germinal matrix-intraventricular hemorrhage (GM-IVH). Head position may affect cerebral hemodynamics and thus may be involved indirectly in development of GM-IVH. Turning the head toward one side may functionally occlude jugular venous drainage on the ipsilateral side while increasing intracranial pressure and cerebral blood volume. Thus, it has been suggested that cerebral venous pressure is reduced and hydrostatic brain drainage improved if the patient is in supine midline position with the bed tilted 30°. The midline position might be achieved in the supine position and, with the use of physical aids, in the lateral position as well. Midline position should be kept, at least when the incidence of GM-IVH is greatest, that is, during the first two to three days of life.

Objectives:

Primary objective

To assess whether head midline position is more effective than any other head position for preventing or extending germinal matrix-intraventricular hemorrhage in infants born at ≤ 32 weeks' gestational age.

Secondary objectives

To perform subgroup analyses regarding gestational age, birth weight, intubated versus not intubated, and with or without GM-IVH at trial entry.

Search strategy:

We used the standard search strategy of the Cochrane Neonatal Review Group to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 8), MEDLINE via PubMed (1966 to September 19, 2016), Embase (1980 to September 19,.2016), and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to September 19, 2016). We searched clinical trials databases, conference proceedings, and reference lists of retrieved articles for randomized controlled trials and quasi-randomized trials.

Selection criteria:

Randomized clinical controlled trials, quasi-randomized trials, and cluster-randomized controlled trials comparing placing very preterm infants in a head midline position versus placing them in a prone or lateral decubitus position, or undertaking a strategy of regular position change, or having no prespecified position. We included trials enrolling infants with existing GM-IVH and planned to assess extension of hemorrhage in a subgroup of infants. We planned to analyze horizontal (flat) versus head elevated positions separately for all body positions.

Data collection and analysis:

We used standard methods of the Cochrane Neonatal Review Group. For each of the included trials, two review authors independently extracted data (e.g., number of participants, birth weight, gestational age, initiation and duration of head midline position, co-intervention with horizontal vs head elevated position, use of physical aids to maintain head position) and assessed risk of bias (e.g., adequacy of randomization, blinding, completeness of follow-up). The primary outcomes considered in this review are GM-IVH , severe IVH, and neonatal death.